This invention relates to improvements in agricultural ground-working implements having both a lowered ground-working mode and a raised transport mode.
It is well known that an agricultural ground-working implement has better ground following characteristics when the hitch of the implement is pivotally attached to the implement frame. An implement with a pivoting hitch, typically referred to as a floating hitch, follows the contour of the ground independently of the elevation of the forward end of the hitch which is attached to the drawbar of the pulling vehicle, i.e. a tractor. The implement frame is typically equipped with gauge wheels located near the front of the frame to set and control the penetration depth of the ground-working tools. The tractive force produced by the tractor acts through the implement hitch to pull the implement tools through the soil. The draft forces are substantial since ground-working tools have a substantial resistance to being pulled through the soil. This draft force is offset from the reaction forces at the ground tools and this creates a moment force on the implement. An implement with a free floating hitch is not restrained from rotation due to this draft moment force. Hence, this moment force causes the implement to rotate in a manner such that the rear of the implement moves upwardly relative to the front of the implement with the result being that the rearwardly disposed ground-engaging tools are raised above the set and desired working depth.
The prior art has provided various forms of systems which act between the implement hitch and the implement frame to counter the draft moment force referred to above in an effort to maintain the implement generally parallel to the ground. The earlier systems were in the form of spring loaded devices while more recent systems have employed hydraulic systems which are designed to act between the implement hitch and the implement frame in such a way as to at least partially counter the draft moment force referred to above.